1. Field of the Invention
The present invention relates to an electrophotographic image forming apparatus, in which a process cartridge including an electrophotographic photosensitive drum is detachably mounted to an apparatus main body to form an image on a recording medium.
The electrophotographic image forming apparatus forms an image on a recording medium by using an electrophotographic image forming process. Examples of the electrophotographic image forming apparatus include, for example, an electrophotographic copying machine, an electrophotographic printer, a facsimile machine, and a word processor. Besides, the recording medium is one on which an image is formed by the electrophotographic image forming apparatus, and paper, an OHT sheet, and the like are included therein, for instance.
The process cartridge contributes, in a state in which the process cartridge is detachably mounted to the apparatus main body of the electrophotographic image forming apparatus, to an image forming process for forming the image on the recording medium. The apparatus main body is a component of the electrophotographic image forming apparatus excluding a cartridge. The process cartridge is a cartridge into which at least one of charging means, developing means, and cleaning means each serving as process means and an electrophotographic photosensitive drum on which an electrostatic latent image is formed are integrally incorporated, and the thus formed cartridge is detachably mounted to the apparatus main body. The process means acts on the electrophotographic photosensitive drum. Therefore, a process cartridge may be a cartridge into which the developing means serving as the process means and the electrophotographic photosensitive drum are integrally incorporated, and the thus formed cartridge is detachably mounted to the apparatus main body. Further, a process cartridge may be a cartridge into which the charging means, the developing means, or the cleaning means serving as the process means and the electrophotographic photosensitive drum are integrally incorporated, and the thus formed cartridge is detachably mounted to the apparatus main body. Note that, the process cartridge, which integrally includes the electrophotographic photosensitive drum and the developing means, is referred to as a so-called integral type. Further, the process cartridge, which integrally includes the electrophotographic photosensitive member and the process means other than the developing means, is referred to as a so-called separation type. That is, the developing means is provided in a developing cartridge, which is different from the process cartridge, and the image formation is performed through a pair of the developing cartridge and the process cartridge. This is referred to as the so-called separation type. Thus, as the process cartridge, the so-called integral type or the so-called separation type process cartridge may be used. Further, as the process cartridge, the so-called separation type process cartridge and the developing cartridge may be used as a pair. The process cartridge can be mounted and removed from the apparatus main body by the user him/herself. Therefore, the maintenance of the apparatus main body may easily be performed.
2. Description of the Related Art
In order to downsize the electrophotographic image forming apparatus, a light emitting member including multiple light emitting elements which are provided side-by-side in a longitudinal direction of the electrophotographic photosensitive drum (hereinafter, referred to as a drum) and emit light for exposing the drum according to image information is used in some cases as an exposure device for the drum. Typical examples of the light emitting member include an LED head array. An exposure device using LEDs needs to have a short focal length, and hence it is necessary to provide an array in the vicinity of the surface of the drum. Thus, in order to replace the process cartridge including the drum, it is essential that the array is spaced away from the drum. Japanese Patent Application Laid-Open No. 2008-224837 discloses such a structure that the array is largely retracted away from the cartridge on an outside of the apparatus main body.
However, the above-mentioned related art has the problems as follows. The array is retracted away from the cartridge on the outside of the apparatus main body, and hence it is probable that the array fouls owing to dust in the outside air, which may cause image defects. Further, the array is easily touched by an operator at the time of replacement of the cartridge, and hence needs to be handled with care.
In other words, it is difficult to simultaneously achieve replacement of the cartridge, prevention of the array fouling, and facility of the operation. As a countermeasure, it is desired that the array stay in the image forming apparatus at the time of replacement of the cartridge.